Originally Posted by
Lord Farringdon
Ex Non-pilot aircrew here.
I have experienced compressor stalls on B727 climb outs after which our erstwhile flight engineer would explain this away as being attributed to the fuselage creating a shadow during high angle climb outs. It certainly felt like we launching a rocket at times from some short fields and this was then sometimes followed by a 'boom boom' in quick succession.Indications on the flight deck always found No 2 was the culprit.
But what causes a compressor to stall on a T7? Is it a function of heavy TO weight and high alpha on climb out and if so, would not both engines suffer in that case? Or is it related to steep climbing turns where the engine turning in might suffer some airflow shadow affect?
The center engine on the 727 was rather notorious for surging/stalling (the only time I've ever experienced a surge on a commercial flight was on a 727 during takeoff). It was the combination of the center "S" duct and an engine (JT8D) that wasn't very tolerant to inlet distortion. It didn't take much to make that "S" duct inlet separate, and once it did the JT8D would almost invariably surge. The good news was that the JT8D was a robust engine and a surge would seldom do damage. It used to be that Pratt engines surged all the time (the JT9D was at least as bad as the JT8D), but it rarely did damage, while GE engines almost never surged, but if it did it, you had to throw it away and install a new one (insert GE light-bulb joke here
). Inlet separation at high angles of attack used to be a big issue resulting an a surge or stall, particularly with Pratt engines. But those days are pretty much behind us.
Now days, inlet and engine designed has improved to the point that an engine surge is nearly always the result of some sort of engine or engine control problem or fault.
I don't know if this Delta crew had any reason to suspect fuel contamination as a potential cause, but if they did that would a good reason to want to land ASAP.